Differences in regulation of Ca(2+)-activated Cl- channels in colonic and parotid secretory cells.
We investigated the regulation of Ca(2+)-activated Cl- channels in cells from the human colonic cell line T84 and acinar cells from rat parotid glands. The participation of multifunctional Ca(2+)- and calmodulin-dependent protein kinase (CaM kinase) II in the activation of these channels was studied using selective inhibitors of calmodulin and CaM kinase II. Ca(2+)-dependent Cl- currents were recorded using the whole cell patch-clamp technique. Direct inhibition of CaM kinase II by 40 microM peptide 281-302 or by 10 microM KN-62, another CaM kinase inhibitor, did not block the Cl- current in parotid acinar cells, whereas in T84 cells KN-62 markedly inhibited the Ca(2+)-dependent Cl- current. We also used the calmodulin-binding domain peptide 290-309 (0.5 microM), which competitively inhibits the activation of CaM kinase II. This peptide reduced the Cl- current in T84 cells by approximately 70% but was without effect on the channels in parotid acinar cells. We conclude that the Ca(2+)-dependent Cl- channels in T84 cells are activated by CaM kinase II but that the channels in parotid acinar cells must be regulated by a fundamentally different Ca(2+)-dependent mechanism that does not utilize CaM kinase II or any calmodulin-dependent process.
Arreola
J
J
Department of Dental Research, University of Rochester Medical Center, New York 14642, USA.
Melvin
J E
JE
Begenisich
T
T
D019307:1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine / Q000031:analogs & derivatives / Q000494:pharmacology; D000818:Animals; D002118:Calcium / Q000494:pharmacology*; D054732:Calcium-Calmodulin-Dependent Protein Kinase Type 2; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000037:antagonists & inhibitors / Q000096:biosynthesis / Q000378:metabolism; D002147:Calmodulin / Q000037:antagonists & inhibitors; D002460:Cell Line; D002478:Cells, Cultured; D018118:Chloride Channels / Q000187:drug effects / Q000502:physiology*; D003106:Colon; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006801:Humans; D007413:Intestinal Mucosa / Q000502:physiology*; D007700:Kinetics; D008297:Male; D010306:Parotid Gland / Q000166:cytology / Q000378:metabolism / Q000502:physiology*; D018408:Patch-Clamp Techniques; D010446:Peptide Fragments / Q000494:pharmacology; D016133:Polymerase Chain Reaction; D051381:Rats; D017208:Rats, Wistar
D002147:Calmodulin; D018118:Chloride Channels; D004791:Enzyme Inhibitors; D010446:Peptide Fragments; C063302:KN 62; D019307:1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine; D054732:Calcium-Calmodulin-Dependent Protein Kinase Type 2; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D002118:Calcium